Convert To n-grams

Converts arrays of strings to arrays of n-grams. Null values in the input arrays are ignored. Each n-gram is represented by a space-separated string of words. When the input is empty, an empty array is returned. When the input array is shorter than n (number of elements per n-gram), no n-grams are returned.

This operation is ported from Spark ML.

For a comprehensive introduction, see Spark documentation.

For scala docs details, see org.apache.spark.ml.feature.NGram documentation.

Since: Seahorse 1.0.0

Input

Port	Type Qualifier	Description
`0`	`DataFrame`	The input `DataFrame`.

Output

Port	Type Qualifier	Description
`0`	`DataFrame`	The output `DataFrame`.
`1`	`Transformer`	A `Transformer` that allows to apply the operation on other `DataFrames` using a Transform.

Parameters

Name	Type	Description
`n`	`Numeric`	The minimum n-gram length.
`operate on`	`InputOutputColumnSelector`	The input and output columns for the operation.

Example

Parameters

Name	Value
`n`	3.0
`operate on`	one column
`input column`	"words"
`output`	append new column
`output column`	"output"

Input

label	words
0	[Hi,I,heard,about,Spark]
1	[I,wish,Java,could,use,case,classes]
2	[Logistic,regression,models,are,neat]

Output

label	words	output
0	[Hi,I,heard,about,Spark]	[Hi I heard,I heard about,heard about Spark]
1	[I,wish,Java,could,use,case,classes]	[I wish Java,wish Java could,Java could use,could use case,use case classes]
2	[Logistic,regression,models,are,neat]	[Logistic regression models,regression models are,models are neat]